A wealth of molecules has appeared in two galaxies that we see as more than 12 billion years ago, revealing information about how the ancient kingdoms formed stars.
One of the distant galaxies, APM 08279+5255, is home to a quasar — an active supermassive black hole at its core that has swallowed a lot of gas — while the other galaxy, NCv1.143, is a a more “normal” galaxy. Both, however, are seen forming stars at a furious rate, hundreds of times more stars than the Milky Way galaxy is currently producing.
Both galaxies were targeted by astronomers using NOEMA, the Northern Extended Millimeter Array, in France. NOEMA can detect millimeter and submillimeter radio waves. Interestingly, the team, led by Chentao Yang of Chalmers University of Technology in Sweden, detected emissions from a whopping 13 different molecules in these two galaxies.
“We see a part of the electromagnetic spectrum that is difficult to observe in nearby galaxies,” Yang said in a news release. “But thanks to the expansion of the universe, the light from distant galaxies like this is shifted to the longer wavelengths that we can see with radio telescopes that observe. [at] submillimeter [wavelengths].”
The discovery forms the largest collection of molecules ever detected in galaxies at great distances (galaxies today are about 20 billion light-years away, and getting bigger due to cosmic expansion).
Among the 13 different types of molecules detected are carbon monoxide, carbon monosulfide, the cyano radical (a radical is a molecule with an unpaired electron in the outer shell of one of its constituent atoms ), the formyl cation (a cation positively charged ion. ), hydrogen cyanide, hydrogen isocyanide, nitric oxide and water. Yang’s team also detected five molecules never seen before in the early universe: Cyclopropenylidene (a highly reactive organic molecule also found on Saturn’s moon Titan), diazenylium (composed of molecular nitrogen and hydrogen ion), radicals in organic molecules. ethynyl, hydronium ions (formed from water molecules and hydrogen ions) and methylidyne radicals (a reactive organic molecule).
All of these molecules are commonly found in the interstellar gas of our Milky Way galaxy, and each provides clues about the environment in which they are found – an environment that we see forming many stars.
“We know that these galaxies are incredible star factories, perhaps one of the largest ever seen in the universe,” Yang said.
The team also found that the quasar in APM 08279+5255, has more excited molecular gas with a higher temperature and density than NCv1.143 as a whole, a consequence perhaps of the activity around the black hole in quasar. Its molecular abundance is similar to galaxies with active black holes in the more modern universe. Similarly, the molecular inventory of NCv1.143 is similar to local starburst galaxies, which are simply galaxies that give birth to many stars, such as the Cigar Galaxy (Messier 82) in the constellation of Ursa Major, the Great Bear. It appears that the chemistry of these types of galaxies was already in place 12 billion years ago.
But not all are equal. The strength of emissions from certain molecules, such as carbon dioxide, combined with the extreme conditions of the two galaxies’ star-forming gas, suggests a so-called “top-heavy initial mass function.” The initial mass function, or IMF, describes how many stars of a given mass are capable of forming, with low-mass stars being more common than high-mass stars. A high-mass IMF would mean that more massive stars formed in the early universe than are forming today. This not only explains why galaxies in the early universe detected by the James Webb Space Telescope are brighter than expected – they contain larger, brighter stars – but also suggests the presence of more massive exploding stars. as supernovae accelerate. the development of the chemistry of these galaxies, which distributes the heavy elements in space.
“The most unusual galaxies in the early universe are finally able to tell their stories through their molecules,” said co-author Pierre Cox, of Sorbonne Université in France.
The findings were published on December 14 in the journal Astronomy and Astrophysics.
Originally posted on Space.com.
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